What simple media tests can tell you about filter problems and rehabilitation
- Authors: Van Staden, Samantha , Haarhoff, Johannes
- Date: 2004
- Subjects: Rapid sand filters , Cleanliness , Measurement
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16658 , uj:15795 , Citation: Van Staden, S.J., & Haarhoff, J. 2004. What simple media tests can tell you about filter problems and rehabilitation. 9th Biennial Conference of the Water Institute of Southern Africa, 2-6 May 2004, Cape Town International Convention Centre, p.1202-1211. ISBN: 1-920-01728-3
- Description: Abstract: Rapid sand filters are expected to continuously produce clean, safe water for many years, during which time some of these filters will inevitably develop some problems. These problems are usually only apparent once the damage is already done, thereby causing expenditure and inconvenience due to rehabilitation. However, if the cleanliness of the media grains is routinely measured, the potential for some of the more serious problems could be detected at an early stage and measures taken to alleviate such problems before serious damage occurs. In 2002 and 2003, the Water Research Group at the Rand Afrikaans University developed a number of tests to quantify filter media cleanliness in a simple yet standard manner. These tests provide information in two important areas. Firstly, they alert the operator when media does not meet an acceptable standard for cleanliness after backwashing. Secondly, they provide pointers to the nature of the residual deposit on the media, suggesting why the media have not been properly cleaned during backwashing. These tests are currently being benchmarked by a series of trials at a number of South African water treatment plants. This paper will provide the details of these tests, together with practical limits for the different parameters. It should make a valuable contribution towards early detection and troubleshooting of filtration problems by operators and managers.
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Measuring the cleanliness of filter media
- Authors: Haarhoff, Johannes , Van Staden, Samantha
- Date: 2006
- Subjects: Water treatment filters , Cleanliness , Measurement
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16675 , uj:15797 , Citation: Haarhoff, J., & Van Staden, S.J. 2006. Measuring the cleanliness of filter media. 9th Biennial Conference of the Water Institute of Southern Africa, 22-24 May 2006, Durban International Conference Centre, 10 p.
- Description: Abstract: Filter media starts its working life as almost pure silica, freshly crushed, sieved, washed and dried. Upon examination a few years later, we find discoloured, often sticky material hardly recognisable as the original. As long as the media retains its granular character and the filter beds stay smooth and level, this is no cause for great concern. However, when the media forms clumps, when cracks become apparent in the bed or the filtrate quality deteriorates for no apparent reason, the media demands closer attention. Such media investigations have been carried out for more than a decade at the Water Research Group of the University of Johannesburg. Drawing on this reservoir of experience and case studies, this paper reviews the different approaches to measuring and expressing the degree of cleanliness of in situ filter media. A conceptual model of the different types of specific deposit on the media is developed first, classifying the specific deposit into those fractions that are washed out by the treatment plant backwash system, the fraction hat can be additionally washed out by a laboratory column, the fraction that needs mechanical agitation to be stripped off the media, and the fraction that can only be chemically stripped. Typical values for the four fractions, as measured during a comprehensive survey of South African water treatment plants, are presented, together with suggested remedial measures for each of the media fractions.
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An experimental study of switching GaN FETs in a coaxial transmission line
- Authors: Joannou, A. J. L.,Pentz, D. C., van Wyk, J. D. and de Beer, A. S.
- Date: 2014
- Subjects: Component for measurements , Device application , Measurement
- Language: English
- Type: Conference
- Identifier: http://hdl.handle.net/10210/16684 , uj:15799 , Citation: Joannou, A. J. L.,Pentz, D. C., van Wyk, J. D. and de Beer, A. S. 2014. An experimental study of switching GaN FETs in a coaxial transmission line. Power Electronics and Applications, 16th European Conference, 26-28 Aug, 2014. Europe. 1-9. DOI:10.1109/EPE.2014.6910756. , DOI:10.1109/EPE.2014.6910756 , DOI: 10.1109/EPE.2014.6910756
- Description: Abstract: The switching characteristics of GaN FETs have not yet been measured accurately because of their small electromagnetic size in relation to the circuit and the electromagnetic environment the measurements are exposed to. Switching GaN FETs in a transmission line will allow for measurements to be taken in an electromagnetically defined environment. The transmission line is adapted to take optimum measurements. This is proven by the waveforms presented.
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Managing HCD risk in tourism organisations – a collaborative responsibility
- Authors: Mara, C.C. , Govender, C.M.
- Date: 2018
- Subjects: Tourism , Measurement , Human capital development (HCD)
- Language: English
- Type: Conference proceeding
- Identifier: http://hdl.handle.net/10210/290655 , uj:31557 , Citation: Mara, C.C. & Govender, C.M. 2018. Managing HCD risk in tourism organisations – a collaborative responsibility.
- Description: Abstract: Tourism faces unique skills gaps and despite investments in human capital development (HCD) most managers are not aware, nor held accountable for the benefits and risk of HCD. This paper explores the responsibility of collaborative role players in managing HCD risk in South African tourism. Interviews with managers reveal the benefits from collective management of HCD risks such as: employee retention, learning transfer, misaligned training needs, disengaged employees and financial mismanagement. The research adds to SA HCD risk knowledge. Practically, the top five SA HCD tourism risks and risk management collaborators are revealed.
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Measurable operational risk in human capital development in the South African service sector
- Authors: Govender, Cookie M. , Jasson, Cashandra C.
- Date: 2018
- Subjects: Service sector , Measurement , Human capital development (HCD)
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/264574 , uj:27997 , Citation: Govender, C.M. & Jasson, C.C. 2018. Measurable operational risk in human capital development in the South African service sector. African Journal of Hospitality, Tourism and Leisure, 7(2):1-16. , ISSN: 2223-814X
- Description: Abstract: The contemporary global business, political, technological and social arena is fraught with challenges, rapid development, continuous change and turbulence, which impact on all employees and the manner in which they are led and managed. Organisations in developed as well as emerging and developing economies, such as South Africa (SA), whether they offer goods or services, are especially affected by radical shifts in operational processes that often impede strategic success. Leaders and managers try to mitigate gaps in performance caused by such turbulence, via change management, organisational development and training and development interventions; however, they have to be extra vigilant of the operational risks that are associated with business operations and human capital development (HCD). Empirical research was conducted to understand and explain the perspectives of South African managers operating in the service sector on the measurable operational risks associated with their investments in HCD initiatives. Qualitative semi-structured interviews were conducted with leaders and managers who were responsible for HCD in selected organisations. Responses were analysed thematically to seek for common patterns and profound narratives. The key finding indicate that the top five risks in HCD are: poor staff retention; lack of learning transfer; misaligned training needs; disengaged trainees; and budget constraints. Risks ranked as high are: staff retention; lack of transfer; competitors; misaligned training; training aversion; limited budget; changing landscape; and training without impact. Further research is recommended to explore whether managers, HCD professionals and training providers measure specific risks, as well compare the operational effectiveness and risks of human capital development.
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